An airfoil can readily be optimized for one set of design constraints consisting of specified values for such parameters as lift, drag, pitching moment, thickness, chord, etc. Achieving this goal for multiple, oftentimes contradictory, sets of design constraints is the objective of the discipline of multi-point design for airfoils. Three basic approaches have, thus far, been employed to achieve multi-point design of an airfoil that will reduce drag and improve lift on a specific airfoil configuration. These approaches have involved (1) determining the contours of a single solid profile from some optimized average of several single point designs, (2) matching multiple design requirements by constructing multi-element wings, and (3) producing an airfoil shape that satisfies several design requirements and to remedy some unwanted flow phenomena with ad-hoc solutions, for example, providing slots to reduce the strength of recompression shocks occurring within a certain narrow speed range.
The first of these approaches can be successfully applied if the design points are sufficiently close spaced together. The second previous approach may cause problems in weight and structure, and sometimes creates new aerodynamic problems in itself due to the need for fairings to accommodate additional gear that must be blended into the overall wing design. The third approach can be useful in fixing a certain aerodynamic problem but usually fails to significantly broaden the operational range of a wing design.
There remains a definite need in the art for an improved airfoil design and process of making same that will satisfy several sets of design constraints over a wide speed range.
Accordingly, it is an object of this invention to provide a new and novel airfoil configuration that becomes self-adaptive to very dissimilar flow conditions, and thus, lends itself to applications in multi-point design for airfoils.
Another object of the present invention is to provide a porous airfoil that vents the airflow flowing over the airfoil to improve the lift and drag characteristics thereof at both subcritical and supercritical conditions.
Another object of the present invention is a process for constructing an airfoil.
Still another object of the present invention is an airfoil having cavities beneath porous upper and lower surfaces.
A still further object of the present invention is a process for making airfoils self-adaptive to dissimilar flow conditions.
Another object of the present invention is a new and novel design process for developing aerodynamic wing designs.